Differential Diagnosis

The patient's symptoms of drastically increased heart rate and shortness of breath that occur at night and subside by morning can be approached by considering various potential causes. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Panic Attack or Anxiety Disorder: The symptoms of increased heart rate and shortness of breath, especially occurring at night and resolving by morning, could be indicative of a panic attack. The trigger could be related to the change in environment or a specific anxiety-provoking thought that occurs during the night.

• Other Likely Diagnoses

  • Sleep Apnea: Although sleep apnea typically presents with daytime sleepiness, it can cause nocturnal awakenings and lead to symptoms like increased heart rate and shortness of breath due to transient hypoxia.
  • Nocturnal Asthma: Asthma symptoms can worsen at night, leading to shortness of breath and potentially increased heart rate due to the body's response to hypoxia.
  • Gastroesophageal Reflux Disease (GERD): GERD can cause nocturnal symptoms, including shortness of breath and increased heart rate, especially if stomach acid refluxes into the lungs.

• Do Not Miss Diagnoses

  • Acute Coronary Syndrome (ACS) or Myocardial Infarction (MI): Although less likely given the recurrent and resolving nature of the symptoms, it's crucial to consider cardiac causes, especially if the patient has risk factors for coronary artery disease.
  • Pulmonary Embolism (PE): A life-threatening condition that can present with sudden onset of shortness of breath and tachycardia, even if the symptoms seem to resolve, a PE should be considered, especially if there are risk factors such as recent travel, immobility, or family history.
  • Cardiac Arrhythmias: Conditions like atrial fibrillation can cause episodic symptoms of palpitations and shortness of breath, which might resolve spontaneously.

• Rare Diagnoses

  • Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodic hypertension, tachycardia, and shortness of breath, often at night.
  • Sleep-Related Eating Disorder or Other Parasomnias: Although less directly related to the symptoms described, these conditions can lead to nocturnal awakenings and potentially to the symptoms experienced by the patient, albeit through different mechanisms.
  • Hyperventilation Syndrome: Can cause shortness of breath and increased heart rate, but it's less likely to have a clear nocturnal pattern without an identifiable trigger.

Each of these diagnoses should be considered in the context of the patient's full medical history, physical examination, and appropriate diagnostic testing to determine the underlying cause of the symptoms.